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I 0 | State of Ohio 

tment of Highways and Public Works 
Division of Highways 

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Instructions to 
Inspectors 

To Guide Them in the Inspection of 
Material and Workmanship Used 
in the Construction of 
State Aid Roads 







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State of Ohio 

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Department of Highways and Public Works 
Division of Highways 


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Instructions to 
Inspectors 

To^Guide Them in the Inspection of 
Material and Workmanship Used 
in the Construction of 
State Aid Roads 


1922 



Columbus, Ohio: 

The F. 1. Heer Printing Co. 
1922 


Bound at State Bindery. 



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~BRARY OF CONGRESS 

PPO M*££ 

»aoi.WiaNt«» DIVISION 












INTRODUCTION 


Careful and competent inspection is one of the most im¬ 
portant elements entering into the construction of any im¬ 
provement. Capable and efficient engineers may be em¬ 
ployed, specifications and plans carefully prepared after the 
most thorough investigation and study of conditions, and the 
best material may be used, but without the proper combina¬ 
tion of materials and careful workmanship at all times in¬ 
sured by continual, careful inspection, the work may fail. 
The idea of inspection is not to cause annoyance or argu¬ 
ments with the contractor, but it is to help him get the best 
results possible by watching careless employes and guard 
against faulty methods and the use of materials which would 
be detrimental to the work. 

These instructions have been prepared with this in mind 
and it is hoped that they will stimulate that close co-operation 
between the contractor and the representatives of this De r 
partment, which is essential for the successful completion of 
the program in which we are all so vitally interested. 

Our Department must have no alibis or excuses to offer 
when the road is completed. 

E. C. Blosser, 

State Highway Engineer. 












i 






















DIVISION OF HIGHWAYS 

COLUMBUS, OHIO 


PURPOSE AND AUTHORITY 

An inspector is placed on the work to keep the depart¬ 
ment informed as to the progress of the work and the manner 
in which it is being done; also to call to the attention of the 
contractor any infringements upon the plans or specifications. 
He is not authorized to approve or accept any portion of the 
work or to issue instructions contrary to the plans and speci¬ 
fications. The inspector must be on the road at all times 
while work is in progress and must give his constant per¬ 
sonal attention to the duties of his position as herein specified. 

He has the authority to reject defective material and to 
suspend any work that is being improperly performed, sub¬ 
ject to the final decision of the Director of Highways and 
Public Works or his duly authorized assistant. The in¬ 
spector is not authorized to revoke, alter, enlarge or relax 
the provisions of the specifications nor to delay the fulfillment 
of the contract by failure to inspect materials and work with 
reasonable promptness. 


Conduct 

The inspector must at all times be gentlemanly and busi¬ 
ness-like, but firm in securing honest work. He is the rep¬ 
resentative of the State on this particular work and should 
endeavor to make a favorable impression upon the public with 
whom he may come in contact. He must not discuss the 
work, the contractor or the Department with persons not 
connected with the same; he must not meddle in politics 

( 5 ) 



6 


while on the work and must confine himself strictly to the 
duties of his position. 


Address 

i 

As soon as he is permanently established on the work the 
inspector must send to the Division Engineer his address and 
also the number of the telephone to which he has access. 

Duties of the Inspectors 

The duties of the inspector may be classified under three 
heads: 

1st. The inspection of methods used in construction, in¬ 
cluding quality of workmanship. The specifications will 
furnish the necessary information for this work. 

2nd. The inspection of both quantity and quality of 
material used. The inspector must assure himself that all 
materials have been sampled, tested and approved by the 
Department of Highways and Public Works before they are 
permitted to be placed in the permanent work. Instructions 
for selecting and shipping samples of materials are incor¬ 
porated herein and should be followed absolutely. 

3rd. The keeping of a daily record of the progress and 
condition of the work. The inspector will be furnished with 
a notebook in which he must keep a daily record of the 
progress and condition of the work. He must also note in 
this book each day events which will in any way have a bear¬ 
ing on possible future disputes, controversies or lawsuits. 
Weekly report blanks will be furnished which must be prop¬ 
erly filled out and sent to the office of the Division Engineer 
within the Division and the State Highway Testing Labora¬ 
tory at the end of each week and should reach them not 
later than the following Monday. In case the above-men¬ 
tioned supplies are not sent, the inspector must make request 
for same without delay to the Division Engineer. 


Templet for Testing Grade 
and Contour of Subgrade 




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4th. The inspector should have on the job at all times 
the following articles : — 

(a) Set of Plans. 

(b) Copy of Specifications. 

(c) Copy of Instructions to Inspectors. 

(d) Inspectors’ Memorandum Book. 

(e) 50 ft. steel tape. 

(f) Templet for checking subgrade under his super¬ 
vision. 

Specifications 

The inspector must thoroughly acquaint himself with the 
requirements of the plans and specifications for the work, and 
must keep a copy of the specifications with him at all times 
while work is in progress on the road. He should take 
particular care in studying the clauses found under the head¬ 
ings “General Provisions” and “Construction Details,” as 
under these headings will be found detailed instructions for 
the proper performance of the work. There must be abso¬ 
lutely no change in the plans or specifications unless ordered 
in writing by the Division Engineer. If there is any point 
about the plans or specifications which he does not fully 
understand the inspector should make a note of the point 
and take it up with the Division Engineer at the first oppor¬ 
tunity. 

Relation of Inspector to the Resident Engineer 

The resident engineer is the inspector’s superior officer 
and his orders must be respected unless they conflict with the 
specifications. The inspector must keep in close touch with 
the resident engineer and assist him as much as possible in 
taking measurements, setting stakes, etc. Many of the stakes 
can be set by the inspector himself. He must see that the 
stakes are not lost or removed, and shall use care in pre¬ 
serving all stakes, reference points and bench marks. He 
must always insist upon a complete understanding of exactly 


9 


what the stakes represent, and see to it that the work is 
carried out in accordance therewith. 

In the absence of the engineer the inspector is in full 
charge of the work and is there to see that the specifications 
are rigidly carried out. All of his orders in accord with the 
plans and specifications must be obeyed; if they are not, his 
duty is to stop the work on that branch in dispute and com¬ 
municate with the resident engineer at once. 

Suggestions for Daily Routine 

1st. Check cars received at unloading station. 

2nd. Record all labor operations and men employed. 

3rd. See that all equipment and materials are ready for 
the day’s operation. 

4th. See that subgrade is in proper condition for the 
pavement and check with the Templet. 

5th. See that sufficient grade stakes are set ahead for 
the grading and pavement. 

6th. Check alignment of forms. 

7th. Examine material arriving on the job. 

8th. Be sure that all materials received are in accord¬ 
ance with the specifications. Necessary samples should be 
taken as per instructions and forwarded to the Department. 

f>th. Check alignment and grade of finished pavement. 

10th. Check up work being done on culvert and bridges 
in advance of the pavement. 

11th. Measure total pavement constructed during the day 
and check materials used. 

12th. Make entry of day’s operation and record all data 
necessary for weekly reports. 

13th. Before leaving the job at night, the inspector 
should see that proper precautions are taken to protect all 


10 


work performed and that all necessary barricades and lights 
are in place. 

14th. Before retiring each night review the specifica¬ 
tions and pay special attention to the articles covering the 
work in hand. 

Dont’s 

DON’T, under any circumstances, make any agreement 
with the contract or for the furnishing of material, teams, or 
labor, nor derive any profit from anything used in the con¬ 
struction of the road. 

DON’T quarrel with the contractor or foreman. If 
possible keep on good terms with them, but at all times be 
firm in holding them to the terms of the contract. 

DON’T give orders to workmen. If work is not being 
done properly notify the foreman or person in charge of the 
work. 

DON’T do work on the road. You are paid to see that 
the work is done properly, not to do it yourself. 

DON’T accept favors from the contractor or try to be 
a “good fellow.” 

DON’T be intimated or “bluffed” by the contractor or 
any of his employees, and report any or all threats, if any be 
made. 

DON’T take orders or follow out suggestions from the 
contractor or from outside parties concerning the manner of 
doing work. Complaints and suggestions by residents along 
the road may be considered and reported, but orders must be 
followed as given by the Department, and plans and specifi¬ 
cations carried out, unless written consent to a change is 
secured from the Department. 

DON’T let the contractor deposit stone or other material 
within the lines of the road at any point until the grading 
and rolling has been properly completed. 















































WATERBOUND MACADAM 


A macadam pavement is constructed of broken stones 
bound together with stone screenings. When water is used 
to assist in the binding, the pavement is known as water- 
bound macadam. 

The specifications as to the treatment of macadam are 
to be your guide at all times, but it is the purpose of this 
paragraph to emphasize and enlarge upon a few particular 
points. In the construction of a macadam road the points 
to be observed are: 

1. The thorough consolidation and specified crown of 
the subgrade or earth bed. 

2. Cleanliness of the stone; it must be free from clay and 
loam. This is especially necessary for screenings. 

3. Size of the stone as given in the specifications. Long, 
flaky pieces or “tailings” must be excluded or broken; they 
will never compact, no matter how much they are rolled. 

4. An excessive quantity of binder must not be used. 
The proportion should be about equal to the voids in the 
broken stones. By using a larger quantity than this the 
amount of rolling is lessened, but at the expense of dur¬ 
ability. 

MACADAM. The pieces of stone should be as nearly 
cubical as possible and be clean and free from dust, dirt 
and screenings, for the reason that is impossible to prevent 
the dust and screenings from being deposited in bunches and 
producing weak places in the road. All excess of dust and 
screenings on the finished road is to be avoided as it ruts 
easily and produces a soft surface. The watering of the 
finishing layer shall be thorough and the watering and rolling 
continued until water flushes over the whole surface and the 
passage of the roller will bring moisture to the partially dry 

(12) 


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Showing the method of filling a water-bound macadam with screenings. 
The men turn the shovel so as to spread the screenings thinly over 
the surface, thus .slowly feeding them into the voids as the rolling 
progresses. In this manner, all the voids are filled and a dense uni~ 
form surface produced. 


















14 


surface, as in the case of concrete when it is tamped. If 
the material sticks to the roller it is clear evidence that there 
is not sufficient water being used. 

The roller operator must not be permitted to dump 
cinders or ashes upon the macadam at any stage of the work. 
Should any cinders appear among the stone the contractor 
will be required to rake back the stone and remove the cinders 
before screenings are applied. 

No screenings shall be dumped on either layer, but they 
should be deposited in piles on the shoulder or at one side 
of the road. The materials should be evenly applied to 
the road with a spreading motion of the shovel, as the rolling 
progresses. The inspector must go over the work as the 
rolling progresses and direct the spreading of sceenings in 
places where voids apper. It is also desirable that there 
shall be no displacement of the rolled stone before the 
spreading of the screenings, but should this occur the roller 
shall be brought into use again immediately before the 
spreading of screenings has begun. The calks of horse 
shoes and wheels of vehicles driven over the surface of the 
rolled stone will tend to loosen and displace the stone, leav¬ 
ing pockets that will be filled with screenings, making weak 
spots in the road. The intention of the specifications is 
that the stone shall be closely packed together and held in 
place until the interstices have been completely filled with 
screenings. The rolling on each course should be continued 
until the stones are brought firmly together and do not move 
ahead of the roller, or when walked over. Any hollows or 
depressions in either layer that develop during the process 
of rolling shall be filled with the same size of stone that 
has been used in the layer and brought to a true grade 
when rerolled. The stone in the depression must be loosened 
before new stone is added. 

Heavy loads of material will not be permitted on the 
surface of an unfinished road, nor after the finishing until 
the road has completely dried. 


15 



Grouting Water-bound Macadam 






16 


The inspector must not permit material of any kind to 
be placed upon the subgrade when it is in a soft or muddy 
condition, or when the ground is full of frost. He must 
see that trenches are cut that will thoroughly drain the 
subgrade during wet weather, and while construction is 
under way. After the road has been completed there will 
be no necessity for subdrainage, as the finished surface 
will act as a roof, completely shedding water from subgrade. 
The inspector must keep a record of the depth of the stone 
in each course of each 100-foot station, after the stone has 
been rolled, but before screenings have been applied. 


BITUMINOUS MACADAM 

When a bituminous cement is used to hold the stone of; 
a macadam pavement in place and make the pavement water¬ 
tight, the pavement is known as bituminous macadam. 

Tar or asphalt binders should be applied only in warm, 
dry weather. The conditions which should be particularly 
observed by the inspector are as follows: 

1. The stone for the upper course should be clean and 
free from dust at the time of applying the binder. If the 
stone should be coated with dust or other fine material, the 
binder would not penetrate and would soon peel off, resulting 
in a raveling of the surface. 

2. The stone should be dry. Moisture will prevent the 
proper adhesion of the binder. 

3. The binder should be applied during warm weather. 
Cold weather has a tendency to chill and stiffen the binder 
before it has time to penetrate, and unsatisfactory work will 
result. The inspector should observe and record the tem¬ 
perature of the binder in the tank from which the application 
is being made as well as the temperature of the air at the 
time the work is being lone. 

The inspector should keep an exact record of the number 
of barrels of tar or asphalt binder that is used on each one 
hundred-foot section of roadway, so that it may be ascer¬ 
tained whether the contractor is using the specified amount 
of material per square yard of surface. 

4. In no case shall the inspector allow bituminous ma¬ 
terial to be applied until he has received a favorable report 
on the samples submitted. 


17 




18 



Applying bituminous material with a pressure distributor mounted on a 
truck. A fine spray of bituminous material thrown against the road 
surface with considerable pressure brings the material into intimate 
contact with the stone surface, thus assuring a bond thereto. 




BRICK ROAD 


In the work on a brick road, the specifications furnish 
information and directions for the greater part of the work, 
but circumstances and conditions usually arise when the in¬ 
spector must be guided by his own judgment and discretion. 

Curb 

The inspector must see: 

1. That the forms are accurately and securely lined and 
braced. 

2. That the inner surfaces of the forms are thoroughly 
drenched before concrete is put in place. 

3. That the surface of the concrete is worked smooth 
by spading and troweling. 

4. That the forms are left in place and the exposed sur¬ 
face of the concrete kept wet until it has thoroughly set. 
Care should be used in removing the forms so as not to 
injure the concrete. 

% . 

Foundation 

The inspector must see: 

1. That the subgrade is thoroughly rolled and compacted, 
and has the specified crown. 

2. That the foundation material is equal to the samples 
submitted and has the required depth and crown, and is well 
rolled. 

% 

3. Where concrete foundation is used, he shall insist 
on all of the details of the specifications being followed. 

4. That the sand used for the cushion coat is of good 
quality, dry and properly luted and rolled before brick are 


19 


20 



Showing Method of Leveling Sand Cushion. 






21 


laid. It is impossible to make an even and uniform cushion 
coat out of wet sand. The surface of this sand cushion or 
bed should have the specified crown as shown by cross-sec¬ 
tion drawing. The cushion coat should have a uniform 
depth, must be of fine sand and must not contain any pebbles 
larger than one-half inch in greatest dimensions. 

Laying 

The importance of care in proper laying the brick can 
hardly be overestimated. After laying no loads should be 
0 permitted on the brick during the process of construction. 
The inspector should see that the lines of brick are kept 
straight and the specifications rigidly carried out in every 
detail. If lug brick are used, see that lugs all face in same 
direction. 

Rolling 

The brick must be thoroughly rolled before filling, as it is 
impossible to get a smooth and uniform surface without ex¬ 
ercising great care in this particular. 

Culling 

After the brick are laid and before rolling, the inspector 
shall carefully examine the same. The brick to be removed 
should be marked with an X and those to be turned with an 
I. This marking may be done with lumber crayon or chalk. 
It is not a duty of the inspector to turn brick or remove 
faulty ones. The inspector should see that the contractor 
removes all culled brick from the work and that they are 
replaced by brick of acceptable quality before the work of 
rolling and filling is undertaken. 

Grout Filler 

See that the proper proportion of sand and cement is 
used. The sand must be fine or it will fail to go down be- 


22 



Rolling Sancl Cushion for Brick Pavement. 



V 


—' > 



Showing Laying of Brick for Brick Pavement. 









24 


tween the bricks. It must also be dry, and it shall be thor¬ 
oughly mixed with the cement, until the mass assumes a uni¬ 
form color without streaks, before the water is added. It 
must be mixed in small quantities, as it is almost impossible 
to keep the sand in suspension in quantities larger than those 
specified. Unless it is perfectly mixed when it is deposited 
on the pavement the water and cement will go to the lower 
portion of the joints between the bricks and the sand will 
remain on top. In mixing the grout it is best to add the 
water slowly, making a mortar first and continue adding 
water until the required consistency is attained. The first 
pouring must be almost as thin as water. The second pour¬ 
ing must be about like thick cream. Experience is required 
to know when you are getting the best results and you are 
advised to study this work very carefully until you have 
determined the exact conditions that are most desirable. The 
pavement must be thoroughly saturated with water before 
beginning the pouring. This is the most particular work in 
the laying of a brick pavement, and the success of the pave¬ 
ment depends more on proper filling than any other one 
thing that enters into the construction except brick. 

Particular care must be exercised in covering the pave¬ 
ment within 15 minutes after the cement grout filler is placed. 
It must be sprinkled and kept damp for several days in order 
to prevent the grout from drying out before it has properly 
set. 

Bituminous Filler 

Where bituminous filler is used the inspector should be 
sure that the brick are thoroughly dry, as damp or wet brick 
defeat the object of the bituminous filler. He should be 
absolutely sure that the joints are completely filled to the 
top and he should keep an accurate record of the number of 
gallons used over a known area. 


2 


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26 



Showing operation of filling brick pavement with tar mastic filler. The 

Squeegee method is used. 









27 

• t 

Monolithic Brick 

The specifications for monolithic brick pavement cover 
the subject thoroughly and no deviation therefrom should be 
made without the consent of the Division Engineer. 



Applying cement grout filler to the brick pavement. 











CONCRETE PAVEMENT 


The construction of a concrete pavement requires the 
constant personal attention of the inspector. He must know 
from personal observation that every batch of concrete placed 
in the pavement contains the proper amounts of coarse and 
fine aggregates, cement and water. 

The following must be carefully observed : 

1. That the cement used has been tested and approved. 

The inspector must send a sample of cement from every 
carload shipment to the laboratory for testing, and no cement 
shall be allowed to go into the concrete pavement that has 
not passed the 7-day test. 

Very frequently the cement is reserved at the ware¬ 
house for the contractor in order that samples may be taken 
and tests made before the cement is shipped. Such cement 
should be marked when sampled so that it can be identified 
when it comes on the job. It is a good plan to sample this 
cement as it comes to the work and have check tests made. 

Cement that has been stored over winter or through a 
wet period must be regarded with suspicion and carefully 
tested before using. 

2. That the stone or gravel and sand have been tested 
and approved. When the proper selection of these materials 
has been made, the inspector must see that the standard of 
quality is conscientiously kept up. 

3. That the side forms and templets are kept clean and 
of true form. There should be a templet for the subgrade 
and a templet for the surface of the pavement. 

The inspector should keep all measurements for laying 
out the templets in his record book so that he can check 
up the templets at any time. 


28 


20 


4. That the subgrade is in true shape and well com¬ 
pacted before any material is hauled onto it, and that it is 
maintained in such shape until concrete is placed. 

5. That the expansion joints are placed in an absolutely 
vertical position. The inspector must carefully examine 
each joint as it is finished and if it is found not vertical must 
be removed at once and replaced by another at a point as 
close to required location as possible. 

6. That the concrete is of the proper consistency and 
special reference to this will be found under the Heading of 
Field Tests on page 43 of these instructions. 

7. That the necessary test cylinders are made and 
shipped according to instructions on page 45. 

8. That the concrete is properly protected and kept wet 
for the period required under the specifications. 


/ 


30 










BITUMINOUS CONCRETE ROAD 


In the construction of a bituminous concrete pavement 
all requirements for curb and foundation are the same as 
given under brick road. 

The determination of the proper mix in the bituminous 
concrete is left to the testing engineer. The inspector must 
notify the Resident Engineer in ample time to allow of such 
determination. The closest inspection is required in the 
preparation of the mixture when same is being placed on the 
road. 

Special attention is called to inspectors on Instructions to 
Road Inspectors on page 66 of these Instructions and should 
be strictly adhered to. 


INSTRUCTIONS FOR COLLECTING AND FOR¬ 
WARDING SAMPLES OF MATERIALS 

General Instructions 

1. The most important point to be observed in the 
selection of samples of materials is to obtain a small quantity 
•or sample which is actually representative of the larger lot 
from which it is taken. 

Where the nature of the material permits, make a care¬ 
ful examination of the entire lot in order to determine its 
general character and the variation between different portions. 
Then select the sample in such a manner that it will repre¬ 
sent all the different grades in the same proportions as they 
occur in the larger lot. 

2. After samples are taken (cement, bituminous ma¬ 
terials, etc.) care should be taken to prevent exposure to air, 
moisture, dirt, or any foreign material. See that all con¬ 
tainers are clean before placing samples therein. This is 
especially important with reference to cans for submitting 
samples of tars, asphalts, oils, etc. Such containers after 
filling must be tightly sealed, preferably with solder, and 
thoroughly cleaned on the outside before being wrapped for 
shipment. Samples of concrete sand must never be shipped 
in unwashed sugar sacks as even a very small per cent, of 
sugar may so effect the sand as to make the test worthless. 

3. Samples of materials proposed to be used in bridge 
construction are to be considered of equal importance with 
those to be used in pavement construction. 

4. Extreme care must be taken in the sampling and in¬ 
spection of materials, and the inspector must not permit the 
contractor to use any construction materials until advised 
that they are acceptable. The inspector shall require that 


33 


rejected materials be removed from the work and not re¬ 
turned. 

5. The inspector must arrange to receive sufficient notice 
from the contractor of car arrivals, so that materials can be 
propely inspected before unloading and without loss of time 
to the contractor. 

6. All samples weighing less than twenty-five (25) 
pounds should be sent by parcel post prepaid. This method 
of delivery is usually more prompt than express. Samples of 
brick, stone, and gravel should be sent by express. In no 
case send samples by freight. 

7. Extreme care, particularly with reference to parcel 
post shipments should be taken in packing samples to avoid 
breakage or leakage of materials in transit at the risk of 
destroying other valuable mail. All liquid materials should 
be properly marked on outside of package: — LIQUID — 
FRAGILE — to conform with Postal Regulations. 

8. By all means see that a card giving complete data 
with reference to the sample is enclosed with each and 
every sample submitted to the testing laboratory. 

9. Send all samples promptly to the State Highway 
Testing Laboratory, Brown Hall, O. S. U., Columbus, 
Ohio. 

10. Samples are to be taken by the Engineer or his au¬ 
thorized representative. 

11. The inspector shall keep a record of all materials 
delivered on the job, all samples submitted, etc., as indicated 
on the Inspector’s Weekly Report Blank. A copy of the 
Weekly Report must be sent to the State Highway Testing 
Laboratory, Brown Hall, O. S. U., Columbus, Ohio, each 
week, as well as to the office of the Division Engineer. 


34 


Stone 

1. When Taken: Samples are to be taken from the 
proposed source of supply at least 7 days before the stone 
is to be accepted or rejected, also unless otherwise directed, 
from every 2,000 cubic yards quarried or delivered, or when 
the quality or appearance of the stone changes, and at such 
other times as may be directed by the engineer. 

2. Where and How Taken: 

(a) Sampling for quality. Samples should be taken 
either from the quarry or from cars as directed by the engi¬ 
neer, and shall be sound interior rock representative of that 
which it is poposed to use. 

(b) Sampling for size. Samples of the crusher product 
shall be taken either at the crusher or from cars as directed 
by the engineer. The samples shall be mixed from runs of 
the crusher, on different days, or, if taken from cars, shall 
be taken from both ends and top and bottom of the car. 

3. Amount and Size of Sample: 

(a) Sampling for quality. A sample shall weigh be¬ 
tween twenty-five (25) and forty (40) pounds, and shall 
consist of pieces of rock at least one and one-half (1£) inches 
in size, and one piece at least three by four by four (3 by 4 
by 4) inches, free from seams and cracks. 

(b) Sampling for size. A sample for size shall weigh 
not less than ten (10) pounds for materials of three-quarters 
(f) inch maximum diameter or less. Samples of materials 
of other sizes shall increase in weight to a maximum of 
approximately sixty (60) pounds varying with the size and 
weight of the largest pieces represented by the sample. The 
sample shall be representative of the product as delivered 
for use. 

Marking and Shipping: Samples shall be shipped 

in tight boxes or bags and shall be accompanied by a card 
(TL-14), in the container or securely attached thereto, stating 
date, county, I. C. H. No., Section letter, by whom sub- 


35 


mitted, owner, location of quarry or source of supply, exact 
location where sample was taken, proposed purpose to which 
the material is to be put, and in case of quarry investigations, 
quantity available, amount and character of stripping, whether 
material from same source has been previously used, where 
and for what purpose, and with what results, haul to nearest 
point on road, average haul to job, character of haul, initial 
cost of rock. Sample should be sent by express to the 
State Highway Testing Laboratory, Brown Hall, O. S. U., 
Columbus. Ohio. 

Notification of sampling (card TL-14), containing the 
above data, shall also be forwarded separately to the labor¬ 
atory immediately upon taking the sample. 

Gravel 

1. When Taken: Samples are to be taken from the 
proposed source of supply at least 7 days before the gravel is 
to be accepted or rejected, also from every 1,000 cubic yards, 
excavated or delivered, or when the quality or appearance of 
gravel changes, and at such othe times as may be directed 
by the engineer. 

2. Where and How Taken: 

(a) Sampling at the pit. Enough sample shall be 
taken to represent an average of the material. An individual 
sample must be taken through a full vertical section of that 
material which it is proposed to use at the point selected. 
Each sample shall be taken from a freshly exposed vertical 
face. 

(b) Sampling from cars. Enough samples shall be 
taken, as directed by the engineer to represent average com¬ 
position. Samples from cars shall be taken from both ends 
and from top and bottom of the car. 


jX' 


36 


3. Amount and Size of Sample: 

(a) Sampling for quality. Samples shall weigh — 

For screened gravel, 25 to 30 pounds. 

For bank gravel, 50 to 75 pounds. 

(b) Sampling for size. A sample for size shall weigh 
not less than ten (10) pounds for material of three-qaurters 
(!) inch maximum diameter or less. Samples of materials 
of other sizes shall increase in weight to a maximum of 
approximately sixty (60) pounds, varying with the size and 
weight of the largest pieces represented by the sample. The 
sample shall be representative of the product as delivered for 
use. 

4. Marking and Shipping: Samples shall be shipped 
in tight boxes or bags and shall be accompanied by a card 
(TL-14) in the container or securely attached thereto, stating 
date, county, I. C. H. No., section letter, by whom submitted, 
owner, location of deposit or source of supply, exact loca¬ 
tion where sample was taken, proposed purpose to which 
the material is to be put, and in case of pit or bank investiga¬ 
tion, quantity available, amount and character of stripping, 
whether material from same source has been previously used, 
where and for what purpose, and with what results, haul to 
nearest point on road, average haul to- job, character of haul, 
initial cost of gravel. Samples should be sent by express to 
the State Highway Testing Laboratory, Brown Hall, O. S. 
U., Columbus, Ohio. 

Notification of sampling (card TL-14), containing the 
above data, shall be forwarded separately to the laboratory 
immediately upon taking of the sample. 

Sand 

1. When Taken: Samples are to be taken from the 
proposed source of supply at least 10 days before the sand 
is to be accepted or rejected, also from every 500 cubic yards 
excavated, or delivered or when the quality or appearance of 




37 


the sand changes, and at such other times as may be directed 
by the engineer. 

9 

2. Where and How Taken: 

(a) Sampling at the pit. Samples shall be taken from 
freshly exposed portions of the deposit as directed by the 
engineer. Mixed samples may be taken if deemed necessary. 

In general, the number of samples shall be sufficient to 
cover the extreme variation of quality in that part of the 
deposit which is proposed to be used. 

(b) Sampling from cars. Enough samples shall be 
taken, as directed by the engineer, to represent average com¬ 
position. Samples from cars shall be taken from both ends 
and from top and bottom of the car. 

3. Amount and Size of Sample: Each sample, 
whether individual or composite, shall weigh between ten (10) 
and fifteen (15) pounds. 

4. Marking 1 and Shipping: Samples shall be shipped 
in tight boxes or bags and shall be accompanied by a card 
(TL-14) in the container, or securely attached thereto, stat¬ 
ing date, county, I. C. H. No., section letter, by whom sub¬ 
mitted, owner, location of deposit or source of supply, exact 
location where sample was taken, proposed purpose to which 
the material is to be put, and in case of source investigation, 
quantity available, amount previously used, where and for 
what purpose, and with what results, haul to nearest point on 
road, average haul to job, character of haul, initial cost of 
sand. Sample should be sent by Parcel Post to the State 
Highway Testing Laboratory, Brown Hall, O. S. U., Colum¬ 
bus, Ohio. 

Notification of sampling (card TL-14) containing the 
above data, shall also be forwaded separately to the labora¬ 
tory immediately’ upon taking of the sample. 


38 


Cement 

1. When Taken: Unless otherwise ordered, samples 
are to be taken from each car of cement delivered at least 
10 days before the cement is to be accepted or rejected. 

2. Where and How Taken: 

Composit Sample.—• If sampled in cars one sample shall 
be taken from one sack in each 40 sacks (or one barrel in 
each 10 barrels) and combined to form one test sample. If 
sampled in bins or warehouses one test sample shall represent 
not more than 200 barrels. 

Cement may be sampled at the mill by any of the fol¬ 
lowing methods that may be practicable, as ordered: 

(a) From the Conveyor Delivering to the Bin. — At 
least five (5) pounds of cement shall be taken from ap¬ 
proximately each 100 barrels passing over the conveyor. 

(b) From Filled Bins by Means of Proper Sampling 
Tubes. — Tubes inserted vertically may be used for sampling 
cement to a maximum depth of 10 feet. Tubes inserted 
horizontally may be used where the construction of the bin 
permits. Samples shall be taken from points well distributed 
over the face of the bin. 

(c) From Filled Bins at Points of Discharge. — Suffi¬ 
cient cement shall be drawn from the discharge openings to 
obtain samples representative of the cement contained in the 
bin, as determined by the appearance at the discharge open¬ 
ings of indicators placed on the surface of the cement di¬ 
rectly above these openings before drawing of the cement is 
started. 

3. Amount and Size of Sample: Each test sample 

should consist of not less than three (3) pounds. 

4. Marking and Shipping: Samples shall be placed 
in tight boxes, tin buckets, or canvas sacks furnished by the 
Department, and shall be accompanied by a card (TL-12) in 
the container, or securely attached thereto, stating date, 
county, I. C. H. No., section letter, by whom submitted, 


39 


sample number, car number and number of barrels repre¬ 
sented. Samples should be sent by Parcel Post to the State 
Highway Testing Laboratory, Brown Hall, O. S. U., Colum¬ 
bus, Ohio. 

Notification of sampling (card TL-12), containing the 
above data, shall also be forwarded separately to the labora¬ 
tory immediately upon taking of the samples. 

Paving Brick 

1. When Taken: Samples are to be taken at least 
four days before the brick are to be accepted or rejected. 
Unless otherwise ordered by the engineer, at least one set 
of samples should be taken for every 100,000 brick delivered. 
If at any time a shipment of brick is received, in which the 
quality of the brick does not appear equal to that of samples 
previously submitted, additional samples should be imme¬ 
diately sent to the Testing Laboratory. 

2. Where and How Taken: 

Samples at point of delivery. — If all the brick in a 
shipment or several shipments of the same make and kind 
of brick appear to be uniform in quality, two samples of twelve 
each may suffice. If in a shipment there appears to be dif¬ 
ferent classes of brick, such as brick that appear to be more or 
less burned than others, a representative lot of twelve brick 
is to be secured for each class of brick, exclusive of the culls. 

Sampling from piles. — In general, samples selected from 
piles shall be as nearly as possible representative of the entire 
run of bricks. Samples from piles shall be taken from as 
many different points corresponding to the length, breadth 
and depth of the pile as possible. In no case shall they be 
confined to the upper or outer few layers. When controversy 
arises regarding the admissibility of certain types or por¬ 
tions of the lot, entire test samples may be selected from 
such types or portions having characteristic appearance in 


common. 


40 


Plant Inspection — For detail instruction covering 
sampling and testing brick at plant see “Instructions to Plant 
Inspectors at Paving Brick Plants.” 

3. Amount and Size of Sample: The number of 
brick required for a standard rattler test is ten. However, it 
is generally advisable to include two extra for each test to 
allow for breakage in transit. 

4. Marking and Shipping: Samples shall be shipped 
in boxes or crates containing twelve brick each and shall be 
accompanied by a card (TL-11) in the container or securely 
attached thereto stating date, county, I. C. H. No., section 
letter, by whom submitted, brand, name of manufacturer, 
sample number, type or quality of brick and number of 
brick represented. Samples should be sent by express to the 
State Highway Testing Laboratory, Brown Hall, O. S. U., 
Columbus, Ohio. 

Notification of sampling (card TL-11) containing the 
above data, shall also be forwarded separately to the labora¬ 
tory immediately upon taking of the sample. 

Bituminous Materials 

Caution. See that all sample cans are tightly sealed. 
Lids should be soldered in at least three places. 

General Recommendation. All samples shall be selected 
to represent as nearly as possible an average of the material, 
care being taken that they are not contaminated with other 
materials. All samples must be sent in perfectly clean tin 
cans. 

In collecting samples, if there is any doubt of the homo¬ 
geneity of the material, individual samples should be taken as 
hereinafter described and such samples should be forwarded 
to the laboratory where tests will be conducted to determine 
the uniformity after which a composite sample of equal parts 
of the individual sample may be mixed for complete tests. 


41 


1. When Taken: Unless otherwise ordered samples 
are to be taken from every car of material delivered, at 
least four days before bituminous material is to be accepted 
or rejected. 

2. Where and How Taken: 

Semi-solid Products. Materials in barrels or drums 
should be sampled by taking samples from not less than o per 
cent of the containers. 

Whenever possible the portion of the sample from each 
drum or barrel should be taken from near the heart of the 
barrel after it has been split open. Where samples must be 
taken from the top of the barrel, the material lying within 
three (3) inches of the surface should not be included. A 
hatchet or any sharp pointed tool is suitable for the purpose 
of digging into the barrel. ( Caution — Do not use kerosene 
on the blade.) The several portions are then to be pressed 
in a can of approximately one-quart capacity, using enough 
material very nearly to fill the can which is then tightly 
covered. 

Tank car shipments are to be sampled through the dome 
by the use of a clean hot shovel or other suitable tool. 

Fluid Products. —• When a fluid material is shipped in 
tank cars and the sample is to be taken directly from the 
tank car to represent an average of the entire tank car con¬ 
tents, one of the following methods is suggested: 

(a) A tin can with a tight removable cover and a wire 
handle is secured, and a number of holes one-eighth of an 
inch in diameter are punched in the cover. This bucket is 
then weighted in any convenient way and lowered slowly 
by means of a cord attached to the handle through the entire 
depth of the tank car, so that the can will be filled with 
material from all depths of the car. This can is then emptied 
into another can of at least one-quart capacity having a screw 
top or other equally tight cap or cover. 

(b) The sample may be taken by lowering a weighted 
bottle or can into the material. The bottle or can should be 


42 


fitted with a stopper which can be removed by a string or 
wire attached to it after it has been lowered to the proper 
depth. Samples should be taken from near the top, middle 
and bottom of the tank. Unless it is evident that pronounced 
variation exists in the different samples they are to be mixed 
and placed in a clean quart tin can for shipment. 

A sample is more representative when the tank car has 
been agitated before the sample is taken. 

Where individual samples are desired to check the uni¬ 
formity of material throughout a tank car it is suggested 
that “thief samples” be taken from top and middle and a 
third sample be taken from the outlet valve through which 
a sufficient amount of bituminous material has been allowed 
to flow in order to clean the valve properly. 

3. Amount and Size of Sample: 

Each sample of asphaltic oil whether individual or com¬ 
posite shall be not less than 1£ pints and not more than one 
quart. For asphalt cements and tar products a sample of one 
pint is sufficient. 

4. Marking and Shipping: Samples shall be shipped 

in tightly sealed, clean tin cans. Under no circumstances 
use glass cans for submitting samples of bituminous m-aterials. 
Each sample shall be accompanied by a card (TL-13) in the 
container or securely attached thereto, stating date, county, 
I. C. H. No., section letter, by whom submitted, brand, name 
of manufacturer, sample number, car number, number of 
barrels represented, and proposed purpose to which the ma¬ 
terial is to be put. Samples should be sent by Parcel Post 
to the State Highway Testing Laboratory, Brown Hall, O. 
S. U., Columbus, Ohio. 

Notification of sampling (card TL-13) containing the 
above data shall also be forwarded separately to the labora¬ 
tory immediately upon taking of the sample. 




FIELD TESTS 


METHOD OF TEST FOR CONSISTENCY OF 

CONCRETE 

The consistency of concrete is very important because 
the strength is greatly reduced by the use of excess water. 
With the “sloppy” concrete sometimes used in pavement and 
building construction, two-thirds to three-fourths of the pos¬ 
sible strength of the concrete may be lost, due entirely to an 
excess of mixing water. 

Scope: This test covers the method to be used, both 
in the laboratory and in the field, for determining the con¬ 
sistency of concrete. 

Apparatus: The test specimen shall be formed in a 
mold of 16 gage galvanized metal, in the form of the lateral 
surface of the frustum of a cone with the base 8 inches in 
diameter, the upper surface 4 inches in diameter, and the 
altitude 12 inches. 

Sample: When the test is made at the mixer, the 
sample shall be taken from the pile of concrete after the 
entire batch has been discharged. When testing concrete 
that has been hauled from a central mixing plant, the sample 
shall 1 be taken from the concrete after it has been dumped on 
the subgrade. 

Procedure: The mold shall be placed on a flat, non¬ 
absorbent surface, such as a smooth plank or a slab of con¬ 
crete, and the operator shall hold the form firmly in place, 
while it is being filled, by standing on the foot pieces. The 
mold shall be filled to about one-fourth of its height with the 
concrete, which shall then be puddled by 20 to 30 strokes with 
a half inch rod pointed at the lower end. The filling shall 


43 


11 



Showing Improper and Proper Consistency of Concrete bv Truncated Cond Test. 














45 


be completed in successive layers similar to the first and the 
top struck off so that the mold is exactly filled. The mold 
shall then be removed by being raised vertically, and at 
exactly three minutes after being filled. The molded con¬ 
crete shall then be allowed to subside until quiescent and 
the height of the speciment measured. 

Slump: The consistency shall be recorded in terms 
of inches of subsidence of the specimen during the test, 
which shall be known as the “slump.” 

Slump = 12 minus (inches of height after subsidence.) 

Note —-This test is not considered applicable where 
there is a considerable per cent of aggregate above 2 inches in 
size. 

Directions for Making Concrete Test Cylinders 

Equipment — The inspector should be provided with 
the following equipment: (a) Paraffined paper molds, meas¬ 
uring 12" x 6" when stapled together, (b) a small shovel, 
(c) a iron rod approximately 18" long, (d) trowel, (e) 
two boards, smooth surfaced, approximately 2' square. 

Sampling Intervals — For every 1,500 lineal feet of 
concrete placed or as may be directed, two 12" x 6" specimens 
should be prepared as hereinafter described. When the speci¬ 
mens are made the inspector should make note of the exact 
station at which samples were taken. 

Preparation of Specimens —The concrete should be 
selected from one batch and be representative of the average 
mix. Sufficient concrete (about six shovels) to mold the 
specimens should be collected with a shovel from different 
parts of the pile of concrete as dumped from the mixer. This 
is placed on one of the boards, the molds having been 
previously placed on the other board. The concrete should 
be placed in each mold, by means of a shovel or large trowel, 
in four layers, the operation to be continuous, at the same 
time the one-half (£) inch iron rod should be used to puddle 


46 


the concrete lightly in order to displace all air and to dis¬ 
tribute the aggregates uniformly throughout. Care should 
be taken not to puddle to excess as this results in bringing 
excess grout to the top and segregates the course aggregate. 
After the cylinder has been filled with concrete and before 
the top surface has been smoothed, the inspector should 
rotate the mold through a half circumference pressing the 
mold firmly downward, so that the ends of the mold rest 
flat on the board at all times. This will insure that both 
top and bottom of the specimens are parallel, and also per¬ 
pendicular to the sides; this manipulation is extremely im¬ 
portant as proper results are not secured unless the concrete 
conforms to the form of the mold. All specimens are to be 
molded in one continuous operation. Do not partially fill 
them at one time and finish them at another. 

Curing —Specimens should be kept under a dampened 
cloth for a one day period, then buried flat under moist earth 
for two days. 

Shipping — On the fourth day after molding the speci¬ 
mens should be carefully packed in a wooden box, partition¬ 
ing the specimens from one another and the box by means 
of sand or paper. Sample identification tag form TL-26, 
properly filled out, must accompany each and every speci¬ 
men submitted. This must include the following informa¬ 
tion — County, inter-county highway number, section letter, 
station or location, proportions, brand, kind or source of 
materials used. “Slump” or Consistency — A duplicate iden¬ 
tification tag should he sent to the Testing Laboratory by 
mail. 

In general, Laboratory tests will be made on specimens 
at the age of 7 days and 28 days, therefore, they should be 
forwarded promptly from the work at the end of the four day 
period. 

If after the work has progressed satisfactorily for two 
weeks and, providing the specimens tested at the age of 7 


47 


days show the concrete to be of good quality and running 
reasonably uniform in strength, the number of specimens may 
be reduced to one for every 1,500 lineal feet if so directed 
by the Testing Engineer or Division Engineer. 

As long, however, as there is any question about any 
factor effecting the quality of the concrete the two specimens 
should be sent to the Laboratory as given in these Instruc¬ 
tions. 

Directions for Making Sieve Analysis of 

Aggregates 

(Field Method) 

Briefly described, the apparatus for this test consists of an 
outside cylindrical container with telescopic cover, a nest of 
semi-cylindrical screens and sieves, a 10 inch rule and a 200 
cc. graduated cylinder. The cylindrical container is exactly 
10 inches in inside depth. As used at present there are in 
each outfit the following screens: f, 4 mesh,, 10 mesh, 20 
mesh, and 50 mesh. In special cases other screens will also 
be used. 

The large cylinder is used when making a screen analysis 
of a coarse aggregate while the 200 cc. glass cylinder is used 
in determining the gradation of sand or other fine aggregate. 

Method for Testing Coarse Aggregate or Mixed 
Aggregates. 

The cylinder is filled with the material to be examined, 
which is then screened through the screen or sieve selected. 
The portion retained on the screen is returned to the cylinder 
and the height of the material determined, each 1/10 inch 
corresponding to 1 per cent of the original volume. The 
portion passing the sieve is then screend through the next 
smaller sized screen and determined in the same manner. The 
total amounts as thus obtained always total over 100 per cent 
after screening. To reduce to the basis of 100 per cent divide 
each of the per cents by the sum total. For example, if a 


48 


run of bank gravel shows by measurement 15 per cent passing 
the screen and 95 per cent retained on the 4 mesh screen 
(total 110%) the correct values are 15-^110=13.0% and 
95 -h 110 = 86.4%. 

Method for Testing Fine Aggregates. 

In making a sieve analysis of a sand, fill the 200 cc. 
glass cylinder with the material. If the sand contains an 
appreciable per cent of coarse material retained on a screen, 
first screen through the No. 4 sieve. Pour the material 
retained on the sieve back in the 200 cc. cylinder and read 
directly the number of cubic centimeters. The material is 
then screened through the successive screens, No. 10, No. 20, 
and No. 50 in order. Determine the amounts retained on 
each of the screens and the per cent passing the No. 50 sieve 
as outlined above. After screening, this will total over 
200 cc. To obtain the corrected per cents, divide through by 
the total as described under coarse aggregates : 

Example: 

C.C. % 


Retained on 4-mesh . 20 9.3% 

Passing 4-mesh and retained on 10-mesh.... 60 27.9% 

Passing 10-mesh and retained on 20-mesh.... 50 23.3% 

Passing 20-mesh and retained on 50-mesh.... 40 18.6% 

Passing 50-mesh . 45 20.9% 


Total . 215 100.0% 


Proposed Field Determination of Clay and Silt 

The apparatus used in this test is the same as that de¬ 
scribed under the method of making sieve analysis of aggre¬ 
gates. Two hundred c.c. of the sand or other fine aggregate 
are measured in the graduated cylinder and transferred to a 
one quart glass fruit jar with lid. Water is added and the 
sand washed by agitation. The large mineral Articles are 
allowed to settle and the water containing the clay and silt 









49 


is poured into the large cylindrical container. The opera¬ 
tion of washing with new portions of fresh water is repeated 
until the wash water remains clear. The water in the large 
container is allowed to stand over night to permit the clay 
and silt to settle out. The clear supernatant water is then 
poured off and the sediment of clay and silt remaining is 
transferred to the 200 c.c. graduated cylinder. Water is added 
to bring the contents of the graduated cylinder to 200 c.c. 
The volume of sediment in the cylinder is determined at the 
end of three hours. This volume divided by 2 gives the per¬ 
centage by volume of clay and silt on a wet basis, three hours 
standing. This value is usually from 2 to 4 times the value 
obtained when determining the clay and silt by dry weight. 
If we assume, therefore, that the specifications require not 
more than 3 per cent of clay and silt by dry weight, less than 
6 per cent by volume of clay and silt would indicate that the 
fine aggregate complies with the specifications while more 
than 12 per cent by volume of clay and silt would indicate 
an excess of material removed in washing. Between 6 and 
12 per cent would indicate that sample was doubtful and 
that sample should be sent to Laboratory for official test. 

Field Colorimetric Test for Organic Impurities in 

Sands 

Equipment. 

12 oz. graduated bottle. 

Vials containing 5 grams of Sodium Hydroxide (Caustic 
Soda). 

1 Aluminum Beaker. 

Preparation. 

Fill the bottle with water to the 6 oz. graduation, then 
pour into beaker, and add the stick of caustic from one of 
the vials and stir until dissolved. 


50 


Method. 

Fill the bottle to the 4£ oz. mark with the sand to be 
tested, add the solution of sodium hydroxide until the volume 
of the sand and solution, after shaking, amounts to 7 oz. 
Shake thoroughly, and allow to stand over night. Observe 
the color of the clear liquid above the sand. 

Interpretation. 

If the liquid is colorless, or has a light yellow color, the 
sand may be considered satisfactory insofar as organic im¬ 
purities are concerned. On the other hand, if a dark colored 
solution from dark red to black is obtained, the sand should 
be considered of doubtful character, and its use forbidden 
pending results of the usual strength tests in the Laboratory. 




INSTRUCTIONS TO PLANT INSPECTORS AT 
PAVING BRICK PLANTS 

The duties of the inspector include the following: 

A. Inspection of the Rattler and Abrasive charge. 

B. Selection and testing of samples from the cars or 
kilns. 

C. Supervision of the loading of cars. 

D. Submitting reports covering the work done and 
shipments made. 

A. Inspection of the Rattler. Upon the arrival at 
the plant the inspector will go over the rattler as to form 
and dimensions, condition of the stave liners, condition and 
weight of the shot and speed of the machine. Any defects 
found should be reported at once to the person in charge of 
the plant with the idea of correcting the conditions found. 
The inspector must satisfy himself of the accuracy of the 
revolution counter by timing it occasionally to guard against 
possible defects in the equipment. 

A brief description of the Rattler and Rattler Test as 
adopted by the American Society for Testing Materials in 
1916 is given in the Appendix of Material Specifications No. 
7. 

B. Selection and Testing of Samples. In general, a 
single sample will be talcen to represent each 10,000 to 15,000 
brick according to conditions described later. 

In the selection of samples the main object is to include 
in the proper proportions brick representing the different 
degrees of burning, shades of color, character of material 
used, and any other factors effecting the wearing quality of 
the brick. No brick are to be included in the sample which 
are cracked or so deformed as to be unfit for laying under 
the Specifications. 51 


Before being placed in the rattler, brick selected for 
testing are to be carefully measured. Measurements for 
length, breadth, and depth, are to be made exclusive of lugs, 
bulges, or grooves, and such dimensions should fall within 
the limits stated in the paragraph of the specifications regu¬ 
lating “Size.” 

The size of brick, obtained by averaging the results of a 
number of determinations, is to be entered as indicated on 
the plant record. 

The inspector will make a visual examination of the 
brick to determine the form, uniformity, freedom from kiln 
marks, cracks and checks in accordance with specification 
requirements defining “Quality” and all brick which are 
clearly unfit for laying must be culled, or the entire lot re¬ 
jected if the condition is general. 

Samples from Kilns. When samples are taken di¬ 
rectly from the kiln, the first set will usually be chosen as 
soon as enough brick have been removed from the front of 
the kiln to permit of obtaining a sample representative of 
both the full width and height of the kiln. Later samples 
are to be taken with the idea of representing three (3) de¬ 
grees of burning in the kiln, one (1) sample to be selected 
from localities (usually the top and sides) to represent the 
hardest burned brick, one sample usually selected from the 
more central portion of any cross section of the kiln to repre¬ 
sent medium burned brick and one sample usually from the 
bottom layers and away from the sides to represent the least 
burned brick. Each of these samples should represent ap¬ 
proximately 15,000 brick. 

The results of the tests on a sample such as first de¬ 
scribed should determine the general average abrasion loss 
and acceptability of the brick according to the specified maxi¬ 
mum loss. The results of the tests on the sets of three (3) 
samples will show the average abrasion loss of the brick 
represented and also the uniformity of the brick in the kiln. 
If the average of the tests in a set of three (3) falls below 


53 


the average specified loss and the difference in loss between 
the highest and lowest testing set is not beyond the permis¬ 
sible range, all bricks represented by the tests should be ac¬ 
cepted. If, however, any one of the three sets should dis¬ 
tinctly fail to meet specification requirements for maximum' 
loss and if the brick represented by the remaining two sets 
would meet requirements both as to average, and variation 
in abrasion loss, then the latter are acceptable provided the 
manufacturer is willing to cull the unsuitable brick. 

In any case where the rattler loss exceeds the specified 
amount solely as a result of extreme wear on one broken 
or defective brick, this result need not be considered and a 
retest should usually be run. 

In any case of doubt, a retest sample should be taken and 
run to represent any lot of bricks which have failed on the 
first test, and if the average of the first test and the retest 
meet the specification requirement, the brick may be accepted. 

Samples Taken from Piles. When the appearance 
of the pile of bricks shows clearly that there is a considerable 
range in the degree of burning, samples to represent each 
of the three degrees should be selected as in the case of 
samples taken from kilns, each sample in general to repre¬ 
sent approximately 10,000 brick and the acceptability of all 
or parts of the piles will be determined in the same way as 
described under “Samples From Kilns.” 

When the surface appearance of the brick does not fur¬ 
nish any indication of their uniformity a sample should be 
taken at random representing approximately 10,00 brick. If 
this sample tests well below the average loss specified the 
one test for each lot of 10,000 brick may suffice. However, 
if the loss approximates the average loss specified or is be¬ 
tween the average and the maximum loss allowed additional 
tests should be made. If the average loss of the tests thus 
made is below the average loss specified and none of the tests 
exceeds the maximum loss permitted then the brick may be 
accepted. 


54 


If the brick should fail to meet either one or both o these 
conditions the brick are to be rejected. 

Samples from Cars. In special cases it may be neces¬ 
sary to take samples of paving brick from cars after they 
are loaded. In this event the following instructions will 
apply. 

In general, follow the same directions as given under 
“Samples from Piles.” Samples are to be taken from as 
many different points as possible corresponding to the length, 
breadth, and depth of the cars. In no case are they to be 
confined to the upper or outer layers. If the brick appear 
uniform in color and quality one sample may be sufficient. 
Iij there are various grades of brick present it may be neces¬ 
sary to take two or possibly three samples in which case the 
brick to be acceptable must show an average loss not to 
exceed the average specified and none of the samples must 
exceed the maximum loss specified. 

C. Supervision of the Loading of Cars. The in¬ 
spector is to supervise in a general way the loading of cars 
in order to determine that the brick loaded are those repre¬ 
sented by his tests and that the culling is such as to exclude 
all cracked, chipped or deformed brick not permitted by the 
specifications as well as all brick from the kilns or piles which 
may have been found unacceptable. 

D. Reports. The inspector is to submit at the end 
of each week to the Engineer of Tests, copies of all reports 
on samples tested. Tests are to be numbered serially begin¬ 
ning with No. 1 for the first test at a given plant in a given 
year. The inspector is also required to submit a weekly 
report on the proper blank form giving a complete record 
of the shipments made during the week. 

The inspector is to send a postal card notice each day to 
the Resident Engineers of the counties to which the brick 
are shipped, giving the car numbers o fall cars of acceptable 
brick shipped from the plant on that day. 


At the end of each month the inspector is to submit to 
the Engineer of Tests a Monthly Report on the proper blank 
form, giving a summary of the total number of brick shipped 
to each job during the month. This report is to show also 
the actual number of days employed on the inspection and 
the amount of the inspection charges allowed by the State. 


INSTRUCTIONS TO PLANT INSPECTORS 
AT ASPHALT PAVING PLANTS 


The inspector’s duties include the following: 

(1) To test or examine all materials used in the mixture. 

(2) To determine whether the proper percentage or 
weight of each material is used. This includes checking the 
accuracy and capacity of the various scales and measures 
used in the plant producing the finished mixtures. 

(3) To oversee the process of combination in order to 
see that the temperatures of the ingredients and mixtures are 
within the limits specified, and that the method of propor¬ 
tioning and combining the materials are accurate and thor¬ 
ough. 

(4) To secure representative samples of the completed 
mixtures and of the individual materials as directed. 

(5) To furnish on a daily report, information con¬ 
cerning the location of the contract, name of contractor, the 
kind or brand of materials used, tests made, proportions 
used, quantities of mixtures turned out, samples taken, and 
all general information relative to the operation of the plant 
as required by the daily report blank, and any special in¬ 
structions that may be given. 

A. Inspection of Materials Delivered. 

1. General. Samples of each material used in the 
mixture will be submitted to the Laboratory at the beginning 
of work on each contract. Should source of supply of any 
material received change from that represented by the original 
sample, new samples should be submitted. Samples of all 
materials rejected by the inspector must be forwarded to> 
the Laboratory. 


56 


57 


Sands as Received. Samples of sand will generally 
be taken from each carload that comes into the plant. If it 
has been determined that the sand being supplied is of a 
uniform grade, one sample may be taken to represent as many 
as three carloads, but the inspector must combine material 
from each of the several cars in making up this sample. In 
all cases great care must be taken to see that the sample is 
representative of material delivered. 

Unless otherwise directed, the sieves used in the test 
shall be the Nos. 200, 80, 40, and 10, using either of the fol¬ 
lowing two methods: 

(1) Place the sample (not less than 100 grams) on the 
No. 200 sieve, shake until practically no more material passes, 
weigh the residue, and place it on the No. 80 sieve, and con¬ 
tinue in the same manner successively with the No. 40 and 
No. 10, weighing the residue on the sieve in each case. 

(2) Stack the sieves in order, placing the No. 10 on 
top, and No. 200 on bottom. Pour the sample on the No. 10 
sieve and shake for a period of ten minutes, or until prac¬ 
tically no more material passes. Screening should be finished 
by shaking each screen individually, adding the material that 
passes to the next finer sieve. 

The screen analysis of the sand as received should be 
reported on the reverse side of the Daily Report Sheet, in¬ 
dicating whether the sample represents one car or more. 
Give car numbers and numbe of tons. Note whether the 
sand complies with the requirements of the specifications for 
Sand B. C., Sec. 2-9. 

When two grades of sand are being received for use in 
combination, separate sieve tests' should be made on ship¬ 
ments of each variety, and the resultant combinations cal¬ 
culated. The proportions in which the two kinds of sand 
are combined should be shown on the report. 

2. Stone or Screenings. The methods of selecting 
samples are the same as described under sand. The size of 
the dried sample used for testing should be not less than 


250 grams for fine stone, and if the screenings are very- 
coarse, an amount up to 500 grams may be used. 

Samples of stone for bituminous concrete should be 
screened through the following screens or sieves : f", , \'\ 

10-mesh. If there is an apreciable per cent of fine material 
passing the 10-mesh sieve the sample should be screened 
through the other sieves as used for the sand. 

Shipments of stone are also to be examined for quality, 
freedom from dirt, and all foreign material. 

Coarse stone to be used in binder coarse or Warrenite 
should be screened though the following screens: 11", 

-f", Y, A sample of not less than 2,000 grams should 

be used. With coarse stone particular attention should be 
given to secure a representative sample of the stone de¬ 
livered. 

3. Stone Dust or Portland Cement (For Filler). 

At the beginning of the work a representative sample 
of the dust or filler should be selected and the percentage 
of material passing a No. 200-mesh sieve determined. 

4. Sampling Refined Asphalt and Asphalt Cement. 

When refined asphalt is shipped to the plant in drums 
or barrels, the inspector is to obtain a sample from each 
shipment selected from at least three barrels, and from a 
point not less than three inches below the surface, which 
will be melted together, and the penetration determined. 
Such samples must be melted with a great deal of care to 
avoid local over-heating, but at the same time a temperature 
of at least 300 to 325°F. must be reached. 

The inspector will also note and record the brand name 
marked on the barrel or drum, and penetration, when given. 

5. Testing Asphaltic Cement. 

The inspector will take, as far in advance of use as 
possible, a sample of each tank car of asphaltic cement (in 
case it is shipped this way) and of each tank or still of 
asphaltic cement, and determine the penetration at 77°F. 


59 


In making the penetration test the following rules are 
to be observed: 

(a) The sample is never to be cooled in ice water or 
in air colder than 60°F. 

(b) The sample must stand in air for not less than 30 
minutes and in water at 77°F. for not less than 1 hour. If 
quick results are required, the time in water may be reduced 
to 45 minutes, and the penetration thus obtained checked 
after the full hour has elapsed. A container of at least 
2-gallon capacity should be used as a water bath. 

(c) All the penetration tests must be made with the 
sample under water unless the air temperature happens to 
be 77 °F. 

(d) Keep the needle clean, but never use oily waste or 
cloth in cleaning it. 

(e) If a small sample of asphaltic cement has stood 
in air for more than 3 or 4 hours, it should always be heated 
carefully and gradually to a temperature of about 325°F., 
the top skimmed off if possible, and the balance stirred 
thoroughly before being tested. 

(f) The penetration will be set for each contract. A 
working range of four points either above or below this 
penetration will be allowed. For example, if the penetration 
is set at 50 the range will be from 46 to 54. If at any time the 
results obtained at the plant should show a deviation above the 
maximum or below the minimum, a check determination 
should be made. If on check tests the sample shows a 
greater deviation than that permitted, the use of the material 
must be stopped and the Laboratory communicated with for 
advice. 

B. Inspection of Proportions: 

The inspector will receive instructions in regard to the 
desired proportions of each ingredient that enters into the 
mixture. He must then make all necessary determinations 
of the accuracy of scales, and see that the required per¬ 
centages or proportions are actually being used. 


60 


Having made preliminary sieve analysis on the aggregates 
as delivered, and having determined the most satisfactory 
batch weights to be used, the inspector shall make screen 
tests on the aggregates after they have passed through the 
dryer and screens. The most important tests are those made 
on the materials as they are to be incorporated in the work. 
The samples should be secured by passing a shovel or pan 
through the stream of hot sand and stone as same runs to 
the storage bins or from the storage bins to the mixer. 
Particular attention must be given to the securing of repre¬ 
sentative samples, since it is from these samples that the 
inspector must determine whether the bituminous concrete 
being produced complies with the grading requirements of the 
specifications. The sieve analysis obtained on these samples 
are reported on the Daily Report Sheet under “Mechanical 
Analysis (Per cents). The sand portion, after cooling 
sufficiently to handle, is screened through the sieves as de¬ 
scribed under “Sand as received”. If an appreciable per cent 
of sand is retained on the screen the coarser screens should 
be used as required. 

The stone portion obtained from the stone storage bin as 
described should be screened through the same screens as 
described under “Stone and Screenings”. 

The results of these tests will show: 

(a) When blended sands are being used, the results 
from the sieve analysis of the sand will show whether mixing 
is being carried on satisfactorily. 

(b) Whether separation of sand and coarse aggregate 
by screening has been complete. 

(c) Whether the amount of 200-mesh material originally 
in the sand has been increased or decreased in the drying and 
screening processes. 

If the dried sand is contaminated with stone or if sand 
is being carried over into the stone bin, steps should be taken 
at once to ascertain the cause and correction made to the 
screen if necessary. 


61 


If the screen analysis of the materials as they are used 
in the mixture run reasonably uniform throughout the day, 
it will only be necessary to show on the Daily Report Sheet 
the determinations for one period. It will be well, how¬ 
ever, to make at least two complete tests during the day, one 
in the forenoon and one in the afternoon. If the materials 
are not running uniform more frequent tests should be made. 

To determine the amount of bitumen obtained from a 
given amount of asphaltic cement use the following figures: 
Refined residual or oil asphalts (Mexican, California, Texas, 
etc.), 100% bitumen, refined Bermudez, 95% bitumen, refined 
Trinidad, 56% bitumen. Fluxed Trinidad (asphalt cement) 
will contain a greater percentage of bitumen than that stated, 
depending upon the amount of fluxing oil used. The oil is to 
be considered 100% bitumen and the inspector will compute 
the percentage of bitumen in the asphaltic cement, knowing 
the number of pounds or proportions or refined asphalt and 
flux used. When Trinidad asphaltic cement is purchased, 
fluxed to the proper consistency for use, the percentage of 
bitumen will be secured from the Laboratory. 

Computation of the Grading of the Bituminous Con¬ 
crete. 

The determination of the per cent of each size of aggre¬ 
gate in the finished mixture is to be made and reported as 
indicated on the Daily Report Sheet. This is done as fol¬ 
lows : multiply the batch weight of the sand by the per¬ 
centage weight of each size. For example, supposing 600 
pounds of sand are being used in each batch and that the 
sand has 20% between No. 10 and No. 40 sieves. Then 
600 X -20 = 120 pounds of 10-40 size in the total batch fur¬ 
nished by the sand. The weights of each size contributed 
by the other materials is computed in the same way. 

The total weights of each size is then determined by 
adding the amounts contributed by each material. For ex¬ 
ample, supposing that in the case referred to above that the 
stone portion also contained four (4) per cent of No. 10- 


62 


40 size, and that the batch weight of stone being used 
was 200, then 200 X -04 =8 pounds of this size contributed 
by the stone or a total of 128 pounds in the batch. 

To arrive at the percentage of 200-mesh material in a 
mixture, first determine which of the ingredients contain 
particles of this size. Stone dust or cement, sand, screen¬ 
ings, and Trinidad asphaltic cement may all contribute to 
the total. Determine the percentage contained in each of 
these materials and the proportions of each material used 
in the mixture, from which can be figured the percentage of 
200-mesh material—based on the total mixture, contributed 
by each ingredient. 

To determine the percentage of each size of material it is 
only necessary to divide each of the total weights by the total 
batch weight. If the total batch weight is 1,000 pounds it 
is only necessary to point off one decimal point, thus giving 
percentage direct. 

C. Inspection of Process of Combination. 

The inspector is to take temperatures of the ingredients 
(especially the mineral aggregate) and of the mixtures as 
frequently as possible and is to assist the plant employes in 
every way in keeping the temperatures uniform by notifying 
them of any marked changes that he may observe. 

Should the aggregate be of improper temperature in the 
weighing box, the inspector should endeavor to prevent the 
incorporation of A. C. and in this way avoid the unneces¬ 
sary loss of the batch of completed mixture. The desired 
temperatures at the plant will depend upon the kind of mix¬ 
ture being prepared, the kind of asphalt being used, the 
weather conditions, and the length of haul. The best tem¬ 
perature for raking on the work will be not less than 275°F. 
for sheet asphalt, and other fine graded mixtures. Mixtures 
which contain a high amount of filler, or are prepared with 
Trinidad asphalt, will require slightly higher temperatures 
for proper raking. Mixtures which are made up chiefly of 
stone should range between approximate temperatures of 


63 


225°F. and 325°F. in order to preserve a proper coating of 
asphalt on the surface of the stone. The inspector will be 
instructed as to the temperature range fixed for each contract, 
which will be governed by conditions peculiar to this contract. 
In no case is any mixture to be allowed to leave the plant 
which is at a temperature higher than 375°F. at the time of 
dropping from the mixer. Overheated aggregate may be 
cooled in the mixer before adding the asphalt, but material 
cooled in the mixer to a point below 375°F., after the asphalt 
has been added, will not be acceptable. The lowest ac¬ 
ceptable temperature on the work will be about 225°F. for 
mixtures containing a high percentage of stone, or about 
250°F. for sheet asphalt wearing surface. It is to be under¬ 
stood, however, that these temperatures are not recommended, 
and that only occasional batches will be accepted. 

The inspector is to note on the mixing platform whether 
the scales are being handled carefully, taking care that the 
bucket swings free during weighing, and that the beam is 
brought to a floating position and the bucket drained com¬ 
pletely for each batch. He will also check, or have the 
mixer man check, the tare weight of the empty asphalt 
bucket at frequent intei'vals, so as to take care of any in¬ 
crease or decrease in the amount of asphalt clinging to the 
bucket after each pouring. Particular attention must be 
paid to this point in cool weather, and, in general, at times 
when there is a long interval between loads. 

The inspector is to make certain that the mixer man 
allows the mineral aggregates to become thoroughly mixed 
before the addition of the asphaltic cement. 

D. Sampling Materials and Mixtures. 

Unless otherwise ordered, a daily sample is to be taken 
for Laboratory test of each tank or still of asphaltic cement 
used in the day’s work. The samples are to be placed in 
the 3-oz. round tin boes, the boxes carefully cleaned and the 
lids closed tightly. The inspector is to make his penetration 


64 


tests on the same samples as sent to the Testing Laboratory, 
taking care to drain all water from the needle holes after 
testing. 

Unless otherwise directed, a daily sample of the asphalt 
wearing surface or bituminous concrete, as the case may be, 
is to be taken in a small quantity at a time, from not less 
than ten and preferably more separate batches, molding the 
portions into a compressed block. The final sample of 
asphalt wearing surface should weigh from one-half to one 
pound, and that of bituminous concrete not less than two 
pounds. 

In selecting the portions of the sample care should be 
taken to scrape away the top material in the load, so as to 
avoid dust or unrepresentative material. 

At the beginning of work on each contract, and when¬ 
ever thereafter, the character of materials used in the work 
is changed the inspector shall submit samples of the fol¬ 
lowing quantities to the Testing Laboratory: 

One pint of refined asphalt or A. C. 

One pint of flux. 

Five pounds asphalt sand. 

Fifteen to twenty pounds of crushed stone. 

At the beginning of operations on a given contract the 
samples of each grade of material taken should be numbered 
serially, starting at number one and continuing until the 
completion of the work, using the same serial number for 
both A. C. sample and the bituminous concrete sample for any 
given date. If two samples of A. C. should be sent for 
one day’s work with one sample of bituminous concrete, mark 
the samples “A” and “B”, but use the same serial number 
for each as used for the bituminous concrete. In other 
words, a given serial number should represent the materials 
used on any particular day. These numbers are to be 
scratched or punched clearly on tin cans, and marked with 
red pencil on the surface of bituminous concrete or similar 


65 


samples. Samples are to be shipped immediately to the Test¬ 
ing Laboratory by Parcel Post. 

E. Daily Reports. The inspector shall fill out and 
mail daily reports on the regular printed form, giving all the 
required information. Reports should be in ink. 


INSTRUCTIONS TO ROAD INSPECTORS 


on 

BITUMINOUS CONCRETE WORK 

Preparation of Base for Laying Bituminous Surfaces. 

All foreign material such as mud, dust, or standing water 
must be removed from the base course before the arrival of 
surface mixtures. There is no objection, however, to the 
laying of hot material on damp concrete still retaining mois¬ 
ture from a rain during the previous night. Any portion of 
mortar or aggregat projecting above the fixed grade of t s e 
base, especially along curbing, must be removed by means of 
picks. 

At low points in grade where water will accumulate in 
quantity on the base, drainage is to be provided during con¬ 
struction of base course. In case this detail has been 
neglected the inspector will cause openings of about 1" in 
diameter to be drilled diagonally through the base at the 
junction with header curbing. A stone drain should be 
constructed from the outlet of this opening to the tile drain 
or opening to the tile drain or open ditch. 

Care should be exercised in the painting of curbings, man¬ 
holes, boxes, joints, etc. The specifications must be fol¬ 
lowed to the letter, i. e., the surface to be painted must be 
dry and free from dust and the paint applied in a thin 
uniform coating, the material and methods being given below 
under (a) and (b). 

(a) Asphaltic Cement. When hot asphaltic cement is 
used as a painting material, it should be heated until thor¬ 
oughly liquid, but not above 325°F. Melting the asphaltic 
cement by use of hot tampers will not be permitted. Much 

66 


67 


trouble has been experienced in the past from overheated or 
underheated asphaltic cement. 

(b) Asphalt Cut-back with Naphtha. Asphalt cut-back 
with naphtha should be prepared at the refinery, but may be 
prepared at the plant or on the work by adding and thor¬ 
oughly mixing from 25 to 30% of motor gasoline to asphaltic 
cement which has been heated until it is of liquid consistency. 
Great care must be taken in the preparation and use of this 
material as it is very inflammable. Should the naphtha cut¬ 
back become too thick for application it may be thinned by 
the addition of more motor gasoline. A heavy paint brush 
may be used to advantage in applying this material. 

The asphaltic cut-back with naphtha is considered a 
superior material to asphaltic cement because of greater ease 
of application and also because the latter material is too often 
damaged by successive heating and overheating. 

Delivery of Materials. Should a load or a portion 
of a load of material become stiffened during transit to 
such an extent that it will form in hard lumps and not permit 
uniform distribution by raking, the material must be rejected 
and thrown out. The appearance of free asphalt on the 
surface of a load of binder or bituminous concrete, especially 
after a long haul, is not necessarily an indication that the 
mixture is too rich in bitumen. All mixtures containing 
stone are very likely to show this condition. Lumps of 
very rich material from the surface of the load should, how¬ 
ever, be thrown out as it is extremely important to avoid 
an excess of bitumen. Too rich a mixture will almost in¬ 
variably result in a soft pavement which will become “wavy” 
in warm weather. In general, special care should be used 
with loads that appear to run irregular as to temperature, 
mixture, or otherwise. Material shall not be delivered when 
it is found impossible to receive its initial rolling in day¬ 
light. Canvas covers must be provided by the contractor for 
delivering vehicles so that the delivery heat requirements 
of the specifications can be met. 


68 


The inspector will be provided with an armored ther¬ 
mometer for the purpose of determining temperatures of the 
mateial being received. He must exercise care in the use 
of this instrument against breakage. He will take the tem¬ 
perature of a sufficient number of loads to satisfy himself 
that the material being received is of uniform temperature, 
and within the limits set by the specifications. He will 
record the readings in his note book and be prepared to 
furnish when required the average temperature of each day’s 
run. He must bear in mind that his instrument is expensive 
and extremely fragile and he must exercise care in its use 
against breakage. 

Unloading of Materials. Asphalt Wearing Surface, 
Binder, or Bituminous Concrete should be dumped in piles 
outside of the area on which it is to be spread, beginning at a 
distance of about six to eight feet back of the previously 
raked material. From this point the load should be dis¬ 
tributed over a length corresponding to the distance which a 
single load will cover, but in no case will the material be 
spread along from the truck. 

The mixture must be thrown forward into place, always 
cleaning up the bottom of each pile. The inspector should 
calculate the distance to be covered by each load, and use 
this in connection with the unloading of the trucks and in 
determining that the mixutre is spread to the proper average 
depth. 

Samples. When so instructed, the inspector will lift 
samples of sheet asphalt or bituminous concrete. The method 
of sampling will be in accordance with that described under 
“D” Sampling Materials and Mixtures in the “Instructions 
to Plant Inspectors at Asphalt Paving Plants.” 

Spreading Binder Mixtures. Careless spreading and 
raking of this course should be guarded against. Raking 
must be thorough and the material distributed uniformly, 
avoiding segregation of stone or bituminous mortar. De- 


69 


pressions and other defects in the base must be corrected 
with this course. If a considerable portion of the base shows 
defective construction, the contractor will be required to 
furnish a template cut to the cross section of the finished 
pavement which will be used as a guide in the laying of the 
binder course or bituminous concrete. 

Spreading Surface Mixtures. The inspector must 
supervise dumping of loads of material. Spreading from 
trucks will not be permitted. The hot material must be 
placed in piles far enough ahead of rakers to necessitate 
moving the entire load, and space enough provided for the 
rakers to stand on the base and not on the hot material. In 
casting material from piles to rakers the shovels must be 
turned, thus permitting the compressed material taken from 
the bottom of the pile to be broken up by the rakers. Rakers 
will not be allowed to tramp over or stand in the hot material 
except in case of extreme dense, stiff bituminous concrete 
mixtures, the rakers will be permitted to push the material 
ahead of the rakes, rather than pull it. This will, of course, 
necessitate their standing in the raked material. However, 
this is not regarded as harmful in this type of mixture, but 
in raking sheet asphalt, the rakers will not be permitted to 
stand in the hot material. 

During the process of raking all the material must be 
thoroughly loosened and evenly distributed by the rakes, and 
any material that is lumpy and does not break down easily 
must be wasted, for if left in the pavement, uneven com¬ 
pression will result. Rakes must have tines of sufficient 
length to penetrate the full depth of the loose mixture. 

After the raking has been completed and before rolling 
is started, the inspector should sight along the surface to 
make sure that the material is raked to the proper cross sec¬ 
tion and grade. Do not rely upon the rakers to be perfect 
in this respect. Much better results can be obtained by cor¬ 
recting humps and depressions before rolling is started than 

* 

after initial compression has taken place. 


70 


The depth of the loose material should be checked fre¬ 
quently, making proper allowance (usually from 25% to 
33£%) for compression. It frequently happens that the 
depth of loose raked material' will decrease so gradually from 
the required amount that the rakers themselves are not aware 
of the fact. Ordinarily 2h inches to 2f inches of loose 
material is required to give 2 inches of compressed material, 
but the inspector should make determination on this point for 
each particular mixture. 

Compression of the Surface. Tamping. Adjacent to 
curbing, etc., compression will be effected by means of hot 
tamping irons as directed by the specifications. A perfectly 
sealed joint with the curbing, is absolutely essential in the 
water proofing of the pavement and unless the entire surface 
of the pavement is waterproof, disintegration may soon take 
place. In the laying of mixed seal coat as well as other 
surface mixtures, hot tampers should be used along the 
header curbing to produce a sealed joint that will prevent 
water from entering between the curb and the asphalt pave¬ 
ment. In cases where the high curb is used and the grade 
is low, gutters should be tested with running water so as to 
insure sufficient grade for drainage to the desired outlet. 
Tampers should follow directly after the rakers, first form¬ 
ing the joint, then progressing along curbs and structures. 
The use of overheated irons must be avoided. The surface 
of header curb, railway track liners, etc., should be thor¬ 
oughly cleaned of all loose material before rolling of the 
wearing surface begins. 

The Roller. — When possible the roller should be weighed 
in order to determine whether it meets with the specification 
requirements. The roller wheels should be tested with a 
straight edge in order to detect untrue surfaces. Badly worn 
bearings should be replaced before the roller is used. The 
use of a defective roller will cause a wavy and untrue sur¬ 
face. During the first rolling the roller wheels must be kept 
moist in order to avoid the picking up of the material. This 


71 


does not mean, that the roller man is to be permitted to keep 
a constant stream of water playing on the wheels which will 
unnecessarily chill the surface of the pavement. Excessive 
use of water is to be especially guarded against in cold 
weather. The inspector should take note that the holes in 
the spray pipes on the roller are not too large. 

A mixture of kerosene or light fuel oil, and water may 
be used for moistening roller wheels, being somewhat ad¬ 
vantageous for cold weather work, in that the roller wheels 
are kept warm, thus closing up the surface of the pavement 
more rapidly. The use of an oil for this purpose must be 
accomplished with care, avoiding spilling of the oil on the 
pavement or the dragging of the mop, by which it is applied, 
across the pavement. On bituminous concrete mixtures the 
oil sometimes flushes free A. C. to the surface, producing 
spots to which the seal coat will not adhere. If this con¬ 
dition occurs the use of oil must be discontinued. 

Method of Rolling. It is important in the following 
process that the roller moves at a slow but uniform 
speed and that the direction of rolling is not suddenly re¬ 
versed, as this will displace the bituminous mixture. There 
is no definite rule covering the time after spreading when the 
rolling should begin. In coud weather it must, of course, be 
started promptly, but in hot weather it may be necessary to 
delay rolling for a short time in order to allow the material 
to cool, so as to avoid excessive displacement and picking 
up on the roller wheels. In rolling sheet asphalt, if the 
surface of the mixture is too hot, water from the roller will 
usually cause it to blister and adhere to the wheels. When 
this condition arises, rolling should be delayed for a time, 
the roller wheels cleaned off, and the blistered spots raked 
out and brought to grade with fresh loose material. 

In case the roller should cause a displacement of the 
wearing surface, such spots should be loosened at once with 
rakes and restored to the original grade of the loose material 
before being rerolled. This condition will frequently be 


noted at the point where the roller is reversed, that is, at the 
junction of the rolled and unrolled material. By sighting 
over the surface, it may be found that the loose material just 
ahead of the roller has been displaced and its depth cor¬ 
respondingly increased, and a low spot produced in front 
of the line where the roller stopped. 

Do not allow the roller, or any vehicle such as a heavy 
water wagon or truck to stand on the finished pavement 
until it has thoroughly cooled after the final rolling. The 
roller engineer should never be permitted to draw his fire 
on the finished pavement. 

If at any time the roller is temporarily incapacitated, due 
to lack of steam, or water, or for other reasons, the dump¬ 
ing and spreading of material must be discontinued until it 
is again in operation. 

Correcting Defects in the Surface. Before starting 
operations the roller must be inspected for weight and bal¬ 
ance and throughout the work it shall frequently be examined 
for parts that might be out of balance, thus causing variations 
in the surface. As far as possible avoid too much patching 
after the mixture has once been rolled, and make it a point 
to catch all irregularities and honey-combed spots while the 
material is still soft. So called “skin patching” will not be 
permitted. Patches to pavement that has become thor¬ 
oughly chilled will involve the complete removal of the 
wearing surface in area effected. In any case patches must 
be placed against a granular surface. A 10-foot straight 
edge for testing the finished pavement is required in the 
specifications, and must be kept on the work at all times. 
When the straight edge is placed longitudinally with the road¬ 
way, depressions in excess of \ inch in 3 feet or f inch in 
10 feet are an indication that proper workmanship is not 
being obtained. 

During cool weather, or in the use of a load containing 
some cool material which does not rake freely, the surface 


73 


of the pavement is apt to be honey-combed after rolling. If 
these voids are large enough to warrant, have some fine 
material raked over the surface and roll immediately, but 
avoid as far as possible the use of smoothing irons and never 
permit the use of any which are at a red heat. When the 
use of the smoothing iron is required, all work done with it 
should be completed before the pavement has cooled and set, 
as at that time sealing may be accomplished without so great 
danger of coking the material. Slightly porous spots in 
bituminous pavements will usually iron out under traffic 
during war weather, if the porous condition is simply on 
the surface of the pavement. In cold weather construction 
it will be necessary to use extraordinary means of sealing 
honey-combed or porous surfaces. Any such defects that 
remain after final compression must be sealed by hot asphaltic 
cement, spread by tamping irons and covered with dry sand 
which is ironed into the open surfaces. Always after final 
rolling the inspector should examine joints with curbing, 
track liners, etc., to see that these joints are perfectly sealed. 
Any cracks that remain must be sealed with naphtha cut¬ 
back or hot asphaltic cement. 

Joints. During the progress of a single day’s work 
the number of joints should be as few as possible. When 
working during warm weather, and as long as the mixture 
is being received at a steady rate, the roller should not be 
permitted to roll over the end of the raked material, but in 
case there is a delay between loads and the roller does cross 
the joint, rakes should at once be used to loosen the mixture 
and give a bond for the new material. Fresh mixture 
should never be laid against a sealed surface over which the 
roller has passed. Joints at the end of the day’s work must 
be cut in such a manner as to give a complete and satis¬ 
factory bond. In bituminous concrete mixtures, the joint 
must be cut square, and to the full specified depth of the 
pavement, painted with a very thin, uniform coat of A. C. 
and the new mixture placed against it, tamped by hand, and 


74 


sealed with a tamping iron before the roller goes over the 
joint. 

With sheet asphalt wearing surface a properly made lap 
joint will be acceptable, but in every case, the surface which 
has been sealed up by the roller must be cut away, so as to 
expose the fresh grain of the mixture, and there must be 
a vertical cut of three-quarters of the depth of the wearing 
surface. The rope joint will be found very satisfactory. 
The rope should be not less than 1 inch in diameter and 
should be placed across the road about six inches back of the 
joint. When the rolling is completed the wearing surface is 
to be cut away with a pick, back to the depressions left by 
the rope. Painting and the placing of fresh material is to be 
done as above described. 

Interruptions in Work Due to Rain. Mixing at the 
asphalt plant is required to cease when rain sets in, but 
material which is enroute from the plant may be laid if the 
rain is very light; or it should be held on the work in trucks 
or wagons until the rain has stopped, after which it may be 
laid, providing proper care is used to remove puddles of 
water. If a heavy driving rain sets in and continues, ma¬ 
terials which was enroute from the plant at the time must 
be wasted. In no case is mixed seal coat to be laid while 
rain is falling, since a thin layer of this character will be 
chilled very rapidly by the water and fail to give a uniform 
coating over the pavement. 

Use of Hot Mixed Seal Coat. During the laying of 
bituminous concrete requiring a mixed seal coat, this ma¬ 
terial properly protected against rapid loss of heat must be 
kept on the work continuously. Trucks containing the 
bituminous concrete will not be dumped until the inspector 
is satisfied that there is sufficient seal coat on the work to 
cover the bituminous concrete. Placing of the seal coat 
should begin after the roller has completed initial rolling of 
about 75 lineal feet of road, i. e., on a sufficient length to 


give a proper sweep for the movement of the roller. After 
this, the placing of the seal coat should be practically a con¬ 
tinuous operation following after the initial rolling. This 
mixture, however, should not be placed until the roller has 
taken out all of the creases from the bottom course mixture, 
and it should not be brought up too close to the unrolled 
material. 

Laying on Broken Stone Base Course. When a bitu¬ 
minous pavement is laid on a broken stone base course which 
has received a surface treatment, any liquid bituminous ma¬ 
terial which accumulates in depressions or at the edges of the 
road must be broomed out carefully and the treatment must 
have dried out completely before laying is started. Areas 
in which the stone is poorly consolidated must be properly 
compressed before the wearing surface is laid. Also any 
cold patches in the base course in which there is an excessive 
amount of bituminous material must be removed and replaced 
with binder or bituminous concrete. Free screenings coated 
with bituminous material, matted on base, must be removed 
before surface mixture is laid. When an edging is not 
provided, the surface course must be laid against wooden 
edging strips of the depth of the pavement, firmly staked and 
set true to line and grade. Strips that are warped or have 
become worn by use must be thrown out. Mats of excess 
screenings and oil must be removed prior to laying of bitu¬ 
minous surface course. 

Co-operation with the Plant Inspector. The road in¬ 
spector should keep in touch with the plant inspector and 
report as accurately as possible any unusual or unsatisfactory 
conditions noted in the laying and rolling, i. e., mixture which 
is too cold, too rich, not uniform, too close, too open, or any 
similar condition, also any error in the rate of dispatching 
of seal coat or other mixtures. This is a matter that should, 
of course, be left largely to the contractor. The plant in¬ 
spector is not responsible for delays in transit which cause 


loads of material to cool and become too stiff for free raking. 
The road inspector must not fail to communicate to the plant 
inspector at the end of each day, the location by stations of 
the pavement laid that day, advising him of any variations 
from the usual width and depth of pavement that may have 
occurred, also of the amount of material rejected on the 
road, and amount of labor employed. The plant inspector 
must make frequent checks on the number of boxes in dif¬ 
ferent loads and keep the road inspector informed. 


INSTRUCTIONS TO INSPECTORS 
Bridges and Culverts 

Do not attempt to inspect the construction of Bridges 
and Culverts until you have a set of the plans and specifica¬ 
tions which you have studied carefully. 

Examine all bridge and culvert material as soon as pos¬ 
sible after it is delivered on the job, and report to the Resi¬ 
dent Engineer regarding any materials which should be re¬ 
jected. 

Do not allow the contractor to start construction until 
line and grade stakes have been set by the Resident Engineer. 

Make sure that the forms are properly braced and wired 
or bolted so that they will not spread or bulge out of line 
when filled with concrete. 

Forms should be practically water tight. Do not allow 
concrete to be poured when there are cracks in the forms 
where mortar can run out. 

If the shoring sets on mud sills, see to it that wedges 
are placed so that any slight settlement can be taken up. 

Do not allow the contractor to pour concrete against 
the unprotected sides of the excavation. FORMS are re¬ 
quired in all cases. 

When the excavation for piers or abutments is made 
to the depth called for on plans, notify the Resident En¬ 
gineers and do not allow concrete to be poured until he has 
approved the foundation. 

There are five things to look out for in placing rein¬ 
forcing steel: 

1st. That the bars are the right size and length. 

2nd. That they are spaced as called for on the plans. 


77 





Riprap stone piled against the base of a bridge abutment to protect the 

foundation against scour. 









79 


3rd. That they are correctly located. Make sure where 
the drawing shows them to be. This should be checked 
carefully. 

4th. All steel is to be wired in placed before pouring 
concrete. Don’t let the work start with the idea that there 
will be plenty of time to place the steel while the concrete is 
being poured. 

5th. For spans over six feet, do not pour concrete until 
the Resident Engineer has approved the reinforcing steel in 
place. 

If it is nesessary to make construction joints in the con¬ 
crete, their location must be approved by tne Resident Engi¬ 
neer. 

There are five things to watch for while pouring con¬ 
crete : 

1st. That the correct amount of aggregates, cement and 
water are used for each batch and that the time of mixing 
is as called for in specifications. 

2nd. That the mortar is well slushed under and around 
the reinforcing steel in slabs, beams and girders. 

3rd. That spading is well done, especially along surfaces 
which will be exposed. 

4th. That the forms are clean and free from debris and 
that all wooden spacers are removed as the concrete is poured. 
That the concrete is placed in layers as nearly level as pos¬ 
sible. 

5th. That the forms and shoring do not start to bulge or 
.settle. 

If hand mixing of concrete is necessary it must be done 
■on a water tight platform, not on the bare ground. 

Do not allow the contractor to place concrete under water 
•except by special permission fom the Resident Engineer. 

Paint coats for surface finish of concrete are not per¬ 
mitted. 



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